The radar altimeter is the instrument the auto throttles use to know when to go to idle for landing. They had a radar altimeter failure which caused the auto throttles to go to idle way before they should have. All the pilots would have had to do was disconnect the auto throttles and push the power up manually. Or heck don't even disconnect them, simply push them up I've done it hundreds of times it takes almost no strength at all to override the auto throttles even when engaged.

I can't fathom how an experienced crew would let this happen to themselves. Unless there was something else gong on mechanically it is simply unbelievable.